scholarly journals Trans-Axonal Signaling in Neural Circuit Wiring

2020 ◽  
Vol 21 (14) ◽  
pp. 5170 ◽  
Author(s):  
Olivia Spead ◽  
Fabienne E. Poulain
Keyword(s):  
Molecular Mechanisms ◽  
Neural Circuits ◽  
Neural Circuit ◽  
Target Selection ◽  
Synaptic Connectivity ◽  
Recent Advances ◽  
Complex Process ◽  
Circuit Formation

The development of neural circuits is a complex process that relies on the proper navigation of axons through their environment to their appropriate targets. While axon–environment and axon–target interactions have long been known as essential for circuit formation, communication between axons themselves has only more recently emerged as another crucial mechanism. Trans-axonal signaling governs many axonal behaviors, including fasciculation for proper guidance to targets, defasciculation for pathfinding at important choice points, repulsion along and within tracts for pre-target sorting and target selection, repulsion at the target for precise synaptic connectivity, and potentially selective degeneration for circuit refinement. This review outlines the recent advances in identifying the molecular mechanisms of trans-axonal signaling and discusses the role of axon–axon interactions during the different steps of neural circuit formation.

Role of microRNAs in Semaphorin function and neural circuit formation

2013 ◽  
Vol 24 (3) ◽  
pp. 146-155 ◽  
Author(s):  
Marie-Laure Baudet ◽  
Anaïs Bellon ◽  
Christine E. Holt
Keyword(s):  
Neural Circuit ◽  
Circuit Formation

Emerging roles for HOX proteins in synaptogenesis

2018 ◽  
Vol 62 (11-12) ◽  
pp. 807-818 ◽  
Author(s):  
Françoise Gofflot ◽  
Benoit Lizen
Keyword(s):  
Cell Fate ◽  
Synapse Formation ◽  
Neural Circuit ◽  
Target Selection ◽  
Axon Growth ◽  
Current Data ◽  
Cell Fate Specification ◽  
Hox Proteins ◽  
Circuit Formation ◽  
Vertebrate Central Nervous System

Neural circuit formation requires the intricate orchestration of multiple developmental events including cell fate specification, cell migration, axon guidance, dendritic growth, synaptic target selection, and synaptogenesis. The HOX proteins are well-known transcriptional regulators that control embryonic development. Investigations into their action in the vertebrate central nervous system have demonstrated pivotal roles in specifying neural subpopulations, but also in several successive steps required for the assembly of neuronal circuitry, such as neuron migration, axon growth and pathfinding and synaptic target selection. Several lines of evidence suggest that the HOX transcription factors could also regulate synaptogenesis processes even after the process of axonal and dendritic guidance has concluded. Here we will review the current data on HOX proteins in neural circuit formation in order to evaluate their potential roles in establishing neuronal connectivity with specific emphasis on synapse formation and maturation.

scholarly journals The Role of MicroRNAs in Hepatoblastoma Tumors

Cancers ◽  
2019 ◽  
Vol 11 (3) ◽  
pp. 409 ◽  
Author(s):  
Ion Cristóbal ◽  
Marta Sanz-Álvarez ◽  
Melani Luque ◽  
Cristina Caramés ◽  
Federico Rojo ◽  
...  
Keyword(s):  
Signaling Pathways ◽  
Molecular Mechanisms ◽  
Molecular Targets ◽  
Therapeutic Strategies ◽  
Substantial Contribution ◽  
Hepatic Malignancy ◽  
Recent Advances

Hepatoblastoma is the most common hepatic malignancy during childhood. However, little is still known about the molecular mechanisms that govern the development of this disease. This review is focused on the recent advances regarding the study of microRNAs in hepatoblastoma and their substantial contribution to improv our knowledge of the pathogenesis of this disease. We show here that miRNAs represent valuable tools to identify signaling pathways involved in hepatoblastoma progression as well as useful biomarkers and novel molecular targets to develop alternative therapeutic strategies in this disease.

scholarly journals Neurotrophin, p75, and Trk Signaling Module in the Developing Nervous System of the Marine AnnelidPlatynereis dumerilii

2016 ◽  
Vol 2016 ◽  
pp. 1-12 ◽  
Author(s):  
Antonella Lauri ◽  
Paola Bertucci ◽  
Detlev Arendt
Keyword(s):  
Nervous System ◽  
Neuronal Development ◽  
Neural Circuit ◽  
Circuit Development ◽  
Circuit Formation ◽  
Neurotrophic Signaling ◽  
High Degree ◽  
Developing Nervous System

In vertebrates, neurotrophic signaling plays an important role in neuronal development, neural circuit formation, and neuronal plasticity, but its evolutionary origin remains obscure. We found and validated nucleotide sequences encoding putative neurotrophic ligands (neurotrophin, NT) and receptors (Trk and p75) in two annelids,Platynereis dumerilii(Errantia) andCapitella teleta(Sedentaria, for which some sequences were found recently by Wilson, 2009). Predicted protein sequences and structures ofPlatynereisneurotrophic molecules reveal a high degree of conservation with the vertebrate counterparts; some amino acids signatures present in the annelid Trk sequences are absent in the basal chordate amphioxus, reflecting secondary loss in the cephalochordate lineage. In addition, expression analysis of NT, Trk, and p75 duringPlatynereisdevelopment by whole-mount mRNAin situhybridization supports a role of these molecules in nervous system and circuit development. These annelid data corroborate the hypothesis that the neurotrophic signaling and its involvement in shaping neural networks predate the protostome-deuterostome split and were present in bilaterian ancestors.

ADF/n-cofilin–dependent actin turnover determines platelet formation and sizing

Blood ◽  
2010 ◽  
Vol 116 (10) ◽  
pp. 1767-1775 ◽  
Author(s):  
Markus Bender ◽  
Anita Eckly ◽  
John H. Hartwig ◽  
Margitta Elvers ◽  
Irina Pleines ◽  
...  
Keyword(s):  
Actin Filament ◽  
Molecular Mechanisms ◽  
Critical Role ◽  
Actin Dynamics ◽  
Complex Process ◽  
First Time ◽  
Late Stages ◽  
Platelet Formation

Abstract The cellular and molecular mechanisms orchestrating the complex process by which bone marrow megakaryocytes form and release platelets remain poorly understood. Mature megakaryocytes generate long cytoplasmic extensions, proplatelets, which have the capacity to generate platelets. Although microtubules are the main structural component of proplatelets and microtubule sliding is known to drive proplatelet elongation, the role of actin dynamics in the process of platelet formation has remained elusive. Here, we tailored a mouse model lacking all ADF/n-cofilin–mediated actin dynamics in megakaryocytes to specifically elucidate the role of actin filament turnover in platelet formation. We demonstrate, for the first time, that in vivo actin filament turnover plays a critical role in the late stages of platelet formation from megakaryocytes and the proper sizing of platelets in the periphery. Our results provide the genetic proof that platelet production from megakaryocytes strictly requires dynamic changes in the actin cytoskeleton.

scholarly journals Multiple Functions of Draxin/Netrin-1 Signaling in the Development of Neural Circuits in the Spinal Cord and the Brain

2021 ◽  
Vol 15 ◽  
Author(s):  
Giasuddin Ahmed ◽  
Yohei Shinmyo
Keyword(s):  
Spinal Cord ◽  
Axon Guidance ◽  
Neural Circuits ◽  
Neural Circuit ◽  
Deleted In Colorectal Cancer ◽  
Guidance Cue ◽  
Thalamocortical Projections ◽  
The Central Nervous System ◽  
Circuit Formation ◽  
The Brain

Axon guidance proteins play key roles in the formation of neural circuits during development. We previously identified an axon guidance cue, named draxin, that has no homology with other axon guidance proteins. Draxin is essential for the development of various neural circuits including the spinal cord commissure, corpus callosum, and thalamocortical projections. Draxin has been shown to not only control axon guidance through netrin-1 receptors, deleted in colorectal cancer (Dcc), and neogenin (Neo1) but also modulate netrin-1-mediated axon guidance and fasciculation. In this review, we summarize the multifaceted functions of draxin and netrin-1 signaling in neural circuit formation in the central nervous system. Furthermore, because recent studies suggest that the distributions and functions of axon guidance cues are highly regulated by glycoproteins such as Dystroglycan and Heparan sulfate proteoglycans, we discuss a possible function of glycoproteins in draxin/netrin-1-mediated axon guidance.

scholarly journals Strip1 regulates retinal ganglion cell survival by suppressing Jun-mediated apoptosis to promote retinal neural circuit formation

2021 ◽  
Author(s):  
Mai Ahmed ◽  
Yutaka Kojima ◽  
Ichiro Masai
Keyword(s):  
Molecular Mechanisms ◽  
Neural Circuit ◽  
Ganglion Cells ◽  
Plexiform Layer ◽  
Bipolar Cells ◽  
Inner Plexiform Layer ◽  
Retinal Ganglion ◽  
Interacting Protein ◽  
Retina Development ◽  
Circuit Formation

In the vertebrate retina, an interplay between retinal ganglion cells (RGCs), amacrine and bipolar cells establishes a synaptic layer called the inner plexiform layer (IPL). This circuit conveys signals from photoreceptors to visual centers in the brain. However, the molecular mechanisms involved in its development remain poorly understood. Striatin-interacting protein 1 (Strip1) is a core component of the STRIPAK complex, and it has shown emerging roles in embryonic morphogenesis. Here, we uncover the importance of Strip1 in inner retina development. Using zebrafish, we show that loss of Strip1 causes defects in IPL formation. In strip1 mutants, RGCs undergo dramatic cell death shortly after birth. Amacrine and bipolar cells subsequently invade the degenerating RGC layer, leading to a disorganized IPL. Thus, Strip1 promotes IPL formation through RGC maintenance. Mechanistically, zebrafish Strip1 interacts with its STRIPAK partner, Striatin3, to promote RGC survival by suppressing Jun-mediated apoptosis. In addition to its function in RGC maintenance, Strip1 is required for RGC dendritic patterning, which likely contributes to proper IPL formation. Taken together, we propose that a series of Strip1-mediated regulatory events coordinates inner retinal circuit formation by maintaining RGCs during development, which ensures proper positioning and neurite patterning of inner retinal neurons.

scholarly journals Neurexin directs partner-specific synaptic connectivity in C. elegans

eLife ◽  
2018 ◽  
Vol 7 ◽  
Author(s):  
Alison Philbrook ◽  
Shankar Ramachandran ◽  
Christopher M Lambert ◽  
Devyn Oliver ◽  
Jeremy Florman ◽  
...  
Keyword(s):  
Neuromuscular Transmission ◽  
Molecular Mechanisms ◽  
Neural Circuits ◽  
Cholinergic Receptor ◽  
Gabaergic Neurons ◽  
Synaptic Connectivity ◽  
Receptor Clustering ◽  
Molecular Control ◽  
C Elegans ◽  
Excitatory Transmission

In neural circuits, individual neurons often make projections onto multiple postsynaptic partners. Here, we investigate molecular mechanisms by which these divergent connections are generated, using dyadic synapses in C. elegans as a model. We report that C. elegans nrx-1/neurexin directs divergent connectivity through differential actions at synapses with partnering neurons and muscles. We show that cholinergic outputs onto neurons are, unexpectedly, located at previously undefined spine-like protrusions from GABAergic dendrites. Both these spine-like features and cholinergic receptor clustering are strikingly disrupted in the absence of nrx-1. Excitatory transmission onto GABAergic neurons, but not neuromuscular transmission, is also disrupted. Our data indicate that NRX-1 located at presynaptic sites specifically directs postsynaptic development in GABAergic neurons. Our findings provide evidence that individual neurons can direct differential patterns of connectivity with their post-synaptic partners through partner-specific utilization of synaptic organizers, offering a novel view into molecular control of divergent connectivity.

scholarly journals Recent Advances in the Pathogenesis and Treatment of Chronic Lymphocytic Leukemia

PRILOZI ◽  
2014 ◽  
Vol 35 (3) ◽  
pp. 105-120
Author(s):  
Dimitar G. Efremov ◽  
Luca Laurenti
Keyword(s):  
Molecular Mechanisms ◽  
Critical Role ◽  
Cell Receptor ◽  
Lymphocytic Leukemia ◽  
Great Promise ◽  
Next Generation Sequencing Technology ◽  
Recent Advances ◽  
Leukaemic Cells ◽  
Near Future

AbstractChronic lymphocytic leukaemia (CLL) is a common lymphoid malignancy characterized by the expansion and progressive accumulation of mature autoreactive B lymphocytes. The disease is clinically heterogeneous and incurable by standard chemotherapy. A major feature of the disease is the marked dependence of the leukaemic cells on various microenvironmental stimuli, which promote leukaemia cell growth, survival, and drug-resistance. Recently, considerable progress has been made in the understanding of the molecular mechanisms that drive CLL. The identification of recurrent genetic lesions using next generation sequencing technology has provided new data on the pathophysiology of the disease and has improved its prognostication. The recognition of the critical role of the B cell receptor (BCR) in driving the disease has resulted in the development of BCR pathway inhibitors that have the potential to completely transform CLL treatment in the near future. Other novel therapeutic agents, such as BCL2 antagonists and chimeric antigen receptor (CAR)-modified T-cells, are also showing great promise in clinical trials. In this review, we summarize some of these recent advances, with a particular focus on the BCR and corresponding pathway inhibitors.

scholarly journals Mitophagy Regulates Neurodegenerative Diseases

Cells ◽  
2021 ◽  
Vol 10 (8) ◽  
pp. 1876
Author(s):  
Xufeng Cen ◽  
Manke Zhang ◽  
Mengxin Zhou ◽  
Lingzhi Ye ◽  
Hongguang Xia
Keyword(s):  
Neurodegenerative Diseases ◽  
Signaling Pathways ◽  
Neurodegenerative Disorders ◽  
Essential Role ◽  
Molecular Mechanisms ◽  
Potential Role ◽  
Treatment Strategies ◽  
Metabolic Process ◽  
Recent Advances

Mitochondria play an essential role in supplying energy for the health and survival of neurons. Mitophagy is a metabolic process that removes dysfunctional or redundant mitochondria. This process preserves mitochondrial health. However, defective mitophagy triggers the accumulation of damaged mitochondria, causing major neurodegenerative disorders. This review introduces molecular mechanisms and signaling pathways behind mitophagy regulation. Furthermore, we focus on the recent advances in understanding the potential role of mitophagy in the pathogenesis of major neurodegenerative diseases (Parkinson’s, Alzheimer’s, Huntington’s, etc.) and aging. The findings will help identify the potential interventions of mitophagy regulation and treatment strategies of neurodegenerative diseases.

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